True story: A USAF F-105 Thunderchief pilot was shot down over North Vietnam, ejected and landed in the jungle. Coming up on his emergency radio, he was told a rescue mission was on the way, to hide out and to come back up on the frequency in an hour. The pilot waited for what seemed like an hour and called back; he once again was told to call back when the hour was up—in 55 more minutes.
Stressful situations are not limited to combat aviation and affect far more than just time perception. Pilots of all stripes encounter challenging situations ranging from the dire (an in-flight fire), to the threatening (ice accumulation during descent) to the social (struggling through a difficult check flight). How we handle the stress can be just as important as how we handle the challenge.
Anxiety and disruption
Stress is a normal response to threat, with both physiological and cognitive aspects. Let’s talk about how stress can affect pilots’ mental performance. When we encounter a challenging situation, we automatically orient our attention to the situation, assess the nature and degree of threat, and mobilize our mental resources to respond. If we assess the situation as difficult but are confident we can manage it, our performance typically improves. But if we are uncertain we can manage a potentially harmful threat, anxiety may arise and undercut our normal cognitive processes and impair our performance in two fundamental ways.
Anxiety preempts some of working memory’s very limited capacity (see the sidebar on the opposite page). Consequently, mental operations that are normally quite easy, such as calculating time remaining to destination, can become difficult and error-prone. Analyzing the nature of an equipment failure is far more stressful when in flight than when sitting comfortably on the ground.
Stress also disrupts the balance between the top-down and the bottom-up systems that control the direction of our attention, giving too much weight to the bottom-up system. Consequently, it is difficult to systematically direct our attention sequentially to the multiple tasks that must be performed in flight. Our attention may be captured by the most salient stimulus, such as the sound and feel of a door popping open shortly after takeoff. (Ironically, fatal crashes have occurred in this situation, even though in many small aircraft it is not an emergency or even a major threat.) Our attention may also dart around over different aspects of the situation, making it hard to focus on priorities and management (fly the aircraft!).
These two fundamental effects can undermine more complex aspects of a pilot’s mental performance. Two colleagues and I analyzed the errors made by airline crews in highly stressful situations and found that the majority of errors fell into four categories: Inadequate comprehension, interpretation or assessment of a situation (24 percent); poor management of competing task demands (17 percent); inadvertent omission of required actions (also 17 percent); and inadequate communication (14 percent). Accident investigations often attribute accidents to poor decision-making, but we argue that what appears simply to be poor decision-making is actually the consequence of these four underlying types of error.
Automatic or Conscious?
To find ways to protect performance in stressful situations, we need to understand differences between two broad modes in which the brain/mind operates as we perform tasks. One mode involves conscious control. The other is automatic, operating largely outside direct conscious control. Conscious control (also termed controlled or executive processing) is slow and effortful, depending heavily on working memory and top-down control of attention; we can focus on only one task at a given moment. We have to use this mode when dealing with novel situations, analyzing unfamiliar situations and learning new information.
In contrast, automatic processing develops when we practice a specific task consistently over time. This processing is fast and fluid, making limited demands on working memory, and it underlies the many sensory-motor skills involved in flying. It is also central to our ability to recognize and interpret situations, such as recognizing that we are high or low on a glideslope, or that our airplane is not handling normally for some reason.
When you were first learning to drive a car or fly an airplane, you probably found the mental workload quite high because you had to rely almost entirely on conscious processing. However, with extensive practice both driving and flying became much easier as cognitive processing of the tasks involved became largely automatic.
Automatic processing is far less vulnerable to stress because it makes fewer demands on working memory and is less dependent on conscious control of attention.
Countering the Effects
To some, these may be distinctions without much difference: Who cares about the source of the stress or how my brain processes information—I’ve got a problem! The ways we respond to stress in our daily lives can include exercise, meditation, eating right and a host of other methods. Pilots can adopt techniques clinically proven to reduce the stress we experience every day or we can embrace other responses that we know from experience with our bodies seems to help. Even when we unexpectedly encounter an abnormal or emergency situation without these tools, we can manage our stress in the cockpit.
Maintain currency and proficiency, not just in routine aspects of flight but also in aspects we don’t normally encounter. You do practice stall recovery several times a year, don’t you? On the ground you may be able to perfectly describe the stall recovery procedure, but, if it is not practiced to the point of automaticity, you may be slow to respond if it actually happens on the turn from base to final. Also, many general aviation aircraft now have sophisticated avionics systems, but operating them tends to draw heavily on conscious processing, which will be disrupted in threatening situations. Even a simple task, such as looking up airport data, can become difficult in an emergency, so practice using every feature you might need in an emergency.
Research shows that having recently thought about a potential situation substantially improves our ability to quickly retrieve relevant information from long-term memory and to respond (a phenomenon called priming). It is useful to periodically ask ourselves where we would go if we have an engine failure at various altitudes at our home airport, and rehearse what we would do.
A generic rule of not turning back to the runway below some particular altitude is not sufficient. For emergency situations, such as an engine fire, we need to have mentally rehearsed the immediate action items frequently enough that they automatically pop into mind.
Manage workload aggressively. Our study of airline accidents revealed that as crews flew into deteriorating situations, their workload snowballed, and some pilots were no longer able to think strategically. Instead, they just reacted to each new task demand as it arose. With their conscious processes overwhelmed, they were no longer able to step back mentally to reassess their situation and their action plan. When workload builds like this, ditch any task that is not absolutely essential. Buy time. Ask ATC for assistance.
Slow down. We tend to rush in threatening situations, but doing so only increases our vulnerability to error. Also, our vulnerability to cognitive biases—seeing what we expect to see—may go up under stress, so we need to force ourselves to be deliberate and systematic. Point to or touch gauges and instruments to make sure you are reading them correctly. Talk out loud to yourself to articulate your understanding of the situation and your plan of action. What is your plan B, and what cues will tell you it’s time to switch to plan B?
Force yourself to breathe slowly and deeply, which will prevent hyperventilation and assist deliberate cognitive processing.
No pilot is immune to the effects of stress, but with these five techniques we can manage the effects and protect the crucial aspects of our performance.
Working Memory And Attention
The human brain holds an immense amount of information in long-term memory, but retrieving that information into conscious awareness is a time-limited process. To make information readily available for the specific task at hand, the brain activates a tiny subset of long-term memory into what is called working memory for easy manipulation. For example, when adding a column of numbers, the sum of each addition is held momentarily in working memory.
Intuitively, we know what attention is: Focusing the mind on one task or aspect of a situation to the exclusion of all the other possibilities. Attention is controlled by two processes, top-down and bottom-up, which normally work in concert. Top-down processing directs attention to whatever information we need for the task at hand. In contrast, bottom-up processes involuntarily capture our attention when we encounter something in the environment that is salient, sudden, or threatening—for example, a fire-warning bell. The two processes complement each other. Most of the time we need to be able to focus attention on what we are working on, but it is essential to be interruptible when something more urgent happens.
Both working memory and attention are very limited cognitive resources and are easily overwhelmed if we try to do too much at one time. In computer terms, they are both narrow-band and low capacity. When we multitask, we may think we are performing several tasks in parallel, but, in most situations, we are actually switching attention and working memory back and forth between tasks (unless both tasks are highly practiced together and thus largely automated, in which case they fuse into a single task). Multitasking has its own risks, which I will discuss in a subsequent article.
Coping With Stress
While managing stress can be key to handling abnormal situations in flight, the stress we bring to the cockpit also plays a role. Consider these suggestions to help minimize everyday stress:
Defining Stress
According to the FAA’s Pilot’s Handbook of Aeronautical Knowledge (FAA-H-8083-25B), “Stress is the body’s response to physical and psychological demands placed upon it. The body’s reaction to stress includes releasing chemical hormones (such as adrenaline) into the blood and increasing metabolism to provide more energy to the muscles. Blood sugar, heart rate, respiration, blood pressure, and perspiration all increase. The term ‘stressor’ is used to describe an element that causes an individual to experience stress. Examples of stressors include physical stress (noise or vibration), physiological stress (fatigue), and psychological stress (difficult work or personal situations).
“Stress falls into two broad categories: acute (short term) and chronic (long term). Acute stress involves an immediate threat that is perceived as danger. This is the type of stress that triggers a ‘fight or flight’ response in an individual, whether the threat is real or imagined. Normally, a healthy person can cope with acute stress and prevent stress overload. However, ongoing acute stress can develop into chronic stress.
“Chronic stress can be defined as a level of stress that presents an intolerable burden, exceeds the ability of an individual to cope, and causes individual performance to fall sharply. Unrelenting psychological pressures, such as loneliness, financial worries, and relationship or work problems can produce a cumulative level of stress that exceeds a person’s ability to cope with the situation. When stress reaches these levels, performance falls off rapidly. Pilots experiencing this level of stress are not safe and should not exercise their airman privileges. Pilots who suspect they are suffering from chronic stress should consult a physician.”
SUGGESTED READING
Dismukes, R.K., Berman, B.A., & Loukopoulos, L.D. (2007). The limits of expertise: Rethinking pilot error and the causes of airline accidents. Aldershot, U.K.: Ashgate.
Dismukes, R.K., Kochan, J.A., & Goldsmith (2018). Flightcrew errors in challenging and stressful situations. Aviation Psychology and Applied Human Factors, 8, 35-46.
Eysenck, M.W., Derakshan, N., Santo, R., & Calvo, M.G. (2007). Anxiety and cognitive performance: Attentional control theory. Emotion, 7, 336-353. • Lazarus, R.S., & Folkman, S. (1984). Stress, Appraisal, and Coping. New York: Springer
Key Dismukes, PhD, retired as Chief Scientist for Aerospace Human Factors at NASA Ames Research Center. He holds airline transport pilot and glider flight instructor certificates, plus Boeing 737 and Cessna Citation type ratings.
